AMSTERDAM, Netherlands  The Netherlands may have to give up paintings once acquired by the Nazis for Adolf Hitler's collection if a state commission determines that a Jewish art dealer was forced to sell the 227 works, Dutch officials said Wednesday.

The claim filed this summer includes works by 17th-century masters Jan Steen, Gerard Dou and Jacob van Ruisdael once owned by art dealer Nathan Katz. It was submitted by Katz's daughter, Sybilla Goldstein-Katz, who lives in the United States, and her three siblings.

The Nazis bought or stole thousands of artworks during their World War II occupation of the Netherlands. The Netherlands reclaimed many after the German defeat in 1945. The works were returned wherever possible but about 5,000 remained in the possession of the state, said Bob van het Klooster of the Ministry of Culture. Most were distributed to state museums on permanent loan.

The Katz family's claim is the largest ever made to the Dutch government over a single collection in terms of the sheer numbers of disputed works, said Evert Rodrigo of the Dutch Art Collections Institute, which manages state-owned art.

The decision on whether to relinquish the works will hinge on the Dutch Restitution Committee's determination of whether Nathan Katz was forced to sell them.

CODART, a network of curators from Belgium, the Netherlands and Luxembourg, said Katz was coerced into selling many of his works to Alois Miedl, who was directed by Hermann Goering to sweep the Nazi-occupied countries for artworks for Hitler's planned Fuehrer Museum. Goering seized many of the works for his own collection.

Postwar U.S. military records also say Katz bartered a painting by Rembrandt in 1941 to buy a way out of Nazi-occupied Holland for himself and his family. Art historians say that under a deal apparently brokered by the Swiss government, Katz gave up Rembrandt's "Portrait of a Man" in exchange for 25 visas for Spain for his extended family and the release of his mother from Westerbork, a concentration camp for Jews in eastern Holland.

"In order to emigrate from Holland he was obliged to hand over certain valuable oil paintings to the Swiss Consul for the benefit of the German occupational authorities," said a report on Katz by the Office of Strategic Services, the precursor of the CIA, obtained from the U.S. National Archives and Records Administration in College Park, Md.

Katz, who lived in Basel, Switzerland with his immediate family after he left the Netherlands, regained possession of the Rembrandt. As for the other art, the Dutch Art Collections Institute notified state museums last week that the Katz family had filed the claim for works at their institutions.

"Many museums are involved. And not just museums. We also lend to embassies and to official institutions," Rodrigo said.

The national Rijksmuseum in Amsterdam confirmed it also received a letter but declined to say which paintings were involved.

"This claim by the Katz family was not at all expected here," said Christiaan Vogelaar, curator of De Lakenhal Museum in the city of Leiden, which displays seven of the contested paintings.

The works have not been recently appraised. Sorting out their provenance could take anywhere from several months to a year or more.

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Associated Press investigative researcher Randy Herschaft in New York contributed to this story.

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